To provide a spacer for laminating concrete secondary products that is interposed between respective products and leaves no trace on a surface (contact surface of a spacer) even if they are held for a long time.

The spacer 1 for lamination comprises a body 3 that is a long- sized material extending in the width direction of the concrete secondary product 2. A plurality of bodies 3 are disposed at a predetermined interval in the longitudinal direction of the concrete secondary product 2. The spacer 1 also comprises synthetic resin plates 4 that are contact parts with the concrete secondary product 2 of each body 3 and are disposed at both ends at least in the longitudinal direction of the body 3. The spacer 1 is constituted so that only synthetic resin plates 4 contact with the concrete secondary product 2. Thus, contact area with the concrete secondary products 2 is reduced by the synthetic resin plates 4, and the concrete secondary products 2 have no spacer trace and no dirt even when the concrete secondary products 2 are laminated and held for a long time. Many projections 4a are formed on a contact surface with the concrete secondary products 2 of the synthetic resin plates 4 to secure providing of the concrete secondary products 2 having no dirt.